Que 1: What is photocell?
Ans: A photocell or photoresistor is a sensor that changes its resistance when light shines on it.
Que 2: How the intensity of light is related to distance.
Ans: The light intensity is inversely proportional to the square of the distance.
Que 3: What is photoelectric effect?
Ans: The photoelectric effect refers to the emission, or ejection of electrons from the surface of a metal in response to incident light.
Que 4: On which factors does the photo-electric effect depends ?
Ans: frequency of light, intensity of light, nature of material, energy of light and potential difference.
Que 5: What is a capacitor ?
Ans: A capacitor is a two-terminal electrical device that can store energy in the form of an electric charge. It consists of two electrical conductors that are separated by a distance. The space between the conductors may be filled by vacuum or with an insulating material known as a dielectric.
Que 6: What is dielectric substance ?
Ans: The dielectric material is the substance that becomes polarized under the influence of an external electric field.
Que 7: What is dielectric constant ?
Ans: Dielectric constant (ϵr) is defined as the ratio of the electric permeability of the material to the electric permeability of free space.
Que 8: What happens when we put a dielectric between the plates of capacitor /Capacity increases or decreases ?
Ans: Putting a dielectric slab in between the plates of a capacitor its capacitance increases.
Que 9: Name some dielectric materials.
Ans: Solid Dielectrics – Ceramic, Plastic, Mica, and Glass. Dielectric Liquid – Distilled Water. Dielectric Gas – Dry Air, vacuum, nitrogen and helium.
Que 10: What is the relation for magnetic field at the centre of the current carrying coil.
Ans: $$B=\frac{μ_{0}}{4π}.\frac{2πnI}{r}=\frac{μ_{0}nI}{2r}$$
Que 11: What is the angle between earths magnetic field and magnetic field due to current carrying coil in tangent galvanometer ?
Ans: The magnetic needle of a tangent galvanometer is deflected at an angle of 30∘ due to magnet.
Que 12: What is the value of permeability of free space.
Ans: μ0 = 4π×10-7H/m
Que 13: What is the unit of magnetic field.
Ans: The unit of magnetic field is tesla.
Que 14: What is Biot-Savart’s law.
Ans: Biot-Savart law states that the magnetic field due to a tiny current element at any point is proportional to the length of the current element, the current, the sine of the angle between the current direction and the line joining the current element and the point, and inversely proportional to the square of the distance of that point.
Que 15: What is hysteresis ?
Ans: The phenomenon in which the magnetic induction (B) lags behind with respect to the magnetizing field H is called hysteresis.
Que 16: What is energy loss in a hysteresis loop?
Ans: The hysteresis loss instead is the energy entrapped in magnetic materials exposed to a magnetic field in the form of residual magnetization.
Que 17: What is a P-N junction.
Ans: A P-N junction is an interface or a boundary between two semiconductor material types, namely the p-type and the n-type, inside a semiconductor.
Que 18: What is a diode ?
Ans: A diode is a semiconductor device that essentially acts as a one-way switch for current.
Que 19: What is biasing of diode.
Ans: Biasing means providing external energy to. Charge carriers. Charges carriers. Charge carriers to overcome the barrier potential and make them move in a particular direction. The charge carriers can either move towards the junction or away from the junction..
Que 20: In forward bias what is the order of current in diode circuit.
Ans: Forward bias lets the current flow in only one direction, that is the forward direction, from the positive terminal to the negative.
Que 21: What is breakdown voltage?
Ans: Breakdown voltage is the threshold voltage at which the initiation of breakdown occurs.
Que 22: What is ultrasonic wave ?
Ans: Ultrasonic waves are sound waves whose frequencies are higher than those of waves normally audible to the human ear.
Que 23: What is the human audible range ?
Ans: The audible range of frequency for humans is between 20 Hz to 20 kHz.
Que 24: What is the relation between velocity, wavelength and frequency of a Wave?
Ans: A wave covers a distance equal to the wavelength (λ) during one period (T). But reciprocal of the period is equal to the frequency (n) of the waves.
Que 25: What is the least count of ultrasonic wave apparatus ?
Ans: The micrometer screw has a least count of 0.001 cm
Que 26: What is Planck’s contant and its true value
Ans: Planck’s constant, symbolized as h, is a fundamental universal constant that defines the quantum nature of energy and relates the energy of a photon to its frequency.
In the International System of Units (SI), the constant value is 6.62607015 × 10−34 joule/hertz (or joule-seconds).
Que 27: What is the unit of Planck’s constant.
Ans: The value of Planck’s constant in meter-kilogram-second units is 6.62607015 × 10−34 joule second.
Que 28: What is diffraction grating ?
Ans: A diffraction grating defines an optical component with a periodic structure that splits the light into various beams that travel in different directions.
Que 29: What is the specification of the diffraction grating you have used.
Ans: Grating Type: No Preference. Ruled Grating. Holographic. Other.
Grating Design: No Preference. Plane Reflection. Spherical Reflection. Toroidal Reflection. Transmission. Other.
Wavelength Range: No Preference. UV. Visible. IR.
Que 30: What is full form of LASER AND LED.
Ans: LED stands for Light Emitting Diode. LASER stands for Light Amplification by Stimulated Emission of Radiation.